Plant life is susceptible to damage from stress associated with variations in temperature and moisture, injurious chemicals and combinations, and biological attack. Flowers, leaves, and other portions from plants which are cut also rapidly lose their fresh appearance due to the stress caused by such cutting. Substantial efforts have been made to extend the resistance of plants to stress associated with temperature and other causes as well as lengthen the shelf life of flowers, leaves, and other portions from plants. Representative patents which illustrate methods for conditioning plants and portions thereof for stress are as follows:
U.S. Pat. No. 2,805,137 discloses a process for conditioning cut flowers by applying an effective amount of a composition comprising a phenol, a compound selecting from the group consisting of carbonyl-containing compounds and compounds capable of being catabolized by plant enzymes to carbonyl-containing compounds and a compound selected from the group consisting of hydrazines, amines and quaternary ammonium compounds. Among the hydrazines and amines, which are alleged to have antiseptic properties and the ability to lower the surface tension of water and therefore suited for use are mono and diamines such as methylamine. ethylamine. diamines such as ethylene diamine, trimethylenediamine, and polyamines such as triamino methane. tetramethylene-tetramine and hexamethylene-tetramine. The phenol, is present in a proportion by weight of 5-1200 parts, the carbonyl-containing compound from 5,000 to 50,000 parts and the hydrazine or amine at a level from 10-900 parts.
U.S. Pat. No. 4,231,789 discloses the application of long chain polyamine compounds of the general formula H.sub.2 N--R.sub.1 --NH.sub.2 wherein R.sub.1 represents a --(CH.sub.2)n--, where n represents an integer from 4-18 and various polyethylene polyamine amino derivatives thereof as a method for protecting crops from suffering various damages due to temperature, etc. Examples of suitable amines within the formula include tetramethylenediamine, pentamethylenediamine. hexadecamethylenediamine, spermidine an other polyamines. The polyamine is diluted to a concentration generally in the range of 10.sup.-4 to 10.sup.-2 moles per liter and applied as an aqueous formulation.
Naturally occurring polyamines have been widely reported to play a key role in protecting plants under a variety of stresses (Wareing, P.F. d: Plant Growth Substances, 1982, pp. 483-494, Academic Press). There is also an excellent review on the ability of naturally occurring polyamines to protect plants under a variety of stresses by "A. L. Galston (1983), Polyamines as Modulators of Plant Development. Bioscience, Volume 33 No. 6". Examples of natural polyamines tested and deemed suited for such use are: cadaverine (n-pentenediamine), putrescine (n-butylenediamine), spermidine (n-butylene/n-propylene triamine). and spermine (n-propylene/n-butylene/n-propylene tetramine.
U.S. Pat. No. 3,749,566 discloses a method for improving the resistance of rice seed to pre-emergence herbicides by applying an aqueous solution containing about 1% of sodium hypochloride bleaching solution and about 1/8th percent of a dimethylamine or diethanolamine salt of 1,8-napthalic anhydrid or acid.